Plasma processes are used during deposition or etching of various material layers in semiconductor processing. Plasma processing offers many advantages over other alternative processing methods. As an example, low temperature may be used to deposit thin film layers than analogous thermal processes. Similarly, plasma enabled reactive ion etching allows almost vertical (anisotropic) etching of material layers which is not possible with purely chemical etching techniques which are isotropic.
However, plasma processes also have some disadvantages because of the nature of the plasma, which comprises charged ions. During plasma processing charged ions may interact with the workpiece transferring the charge to the workpiece. The charge may be trapped within a region of the workpiece and may have deleterious consequences due to charge damage for the subsequent operation of the device. The susceptibility or degree of device damage depends on the stage of device fabrication and the specific device design.
Hence, what are needed circuits, devices, and methods of manufacturing to reduce plasma-induced damage in a workpiece.